14. As the Court declared in its judgment of 17 December 1970, 11/70, Internationale Handelsgesellschaft (1970) ECR 1125 [referred under lecture 3], the question of a possible infringement of fundamental rights by a measure of the Community institutions can only be judged in the light of Community law itself. The introduction of special criteria for assessment stemming from the legislation or constitutional law of a particular Member State would, by damaging the substantive unity and efficacy of Community law, lead inevitably to the destruction of the unity of the common market and the jeopardizing of the cohesion of the Community.

15. The Court also emphasized in the judgment cited, and later in the judgment of 14 May 1974, 4/73, Nold (1974) ECR 491 [referred under lecture 3], that fundamental rights form an integral part of the general principles of the law, the observance of which it ensures; that in safeguarding those rights, the Court is bound to draw inspiration from constitutional traditions common to the Member States, so that measures which are incompatible with the fundamental rights recognized by the constitutions of those states are unacceptable in the Community; and that, similarly, international treaties for the protection of human rights on which the Member States have collaborated or of which they are signatories, can supply guidelines which should be followed within the framework of Community law. That conception was later recognized by the joint declaration of the European Parliament, the Council and the Commission of 5 April 1977, which, after recalling the case-law of the Court, refers on the one hand to the rights guaranteed by the constitutions of the Member States and on the other hand to the European Convention for the Protection of Human Rights and Fundamental Freedoms of 4 November 1950 (Official Journal C 103, 1977, p. 1).